Bakin karfe ba ya saurin lalacewa, tsatsa ko tabo da ruwa kamar yadda karfe na yau da kullun ke yi. Duk da haka, ba shi da cikakken tabo a cikin ƙananan iskar oxygen, high-salinity, ko matalauta yanayin kewayar iska. Akwai nau'o'i daban-daban da abubuwan da aka gama na bakin karfe don dacewa da yanayin da gami dole ne ya jure. Ana amfani da bakin karfe inda ake buƙatar kaddarorin karfe da juriya na lalata.

Bakin karfe ya bambanta da carbon karfe da adadin chromium da ke akwai. Karfe na carbon da ba shi da kariya yana tsatsa da sauri lokacin da aka fallasa shi da iska da danshi. Wannan fim ɗin baƙin ƙarfe oxide (tsatsa) yana aiki kuma yana haɓaka lalata ta hanyar samar da ƙarin ƙarfe oxide [bayani da ake buƙata]; kuma, saboda yawan ƙarar baƙin ƙarfe oxide, wannan yana kula da faɗuwa da faɗuwa. Bakin karfe ya ƙunshi isassun chromium don samar da fim ɗin chromium oxide, wanda ke hana ci gaba da lalacewa ta hanyar toshe iskar oxygen zuwa saman ƙarfe kuma yana toshe lalata daga yaɗuwa cikin tsarin ƙarfe. Passivation yana faruwa ne kawai idan rabon chromium ya isa sosai kuma oxygen yana nan.